The candidate's background as a Chiropractic Physician specializing in work and sports injuries initiated his interest in rehabilitation science. His scientific work has focused on human cortical motor physiology. His goals include the development of non-invasive cortical stimulation protocols to assist the neurologically impaired restore motor function, and to become an independent scientist skilled in the conduct of clinical trials of movement-related therapeutics. Three leading mentors have been nominated for the study: Professors W Z Rymer (translational), J C Rothwell (physiology), and T J Schnitzer (clinical trials). The Rehabilitation Institute of Chicago (RIC) is an ideal environment in which to conduct the proposed research. RIC admits over 300 acute stroke survivors and treats over 1000 chronic stroke survivors annually. Dr. R. Harvey, (Director of Stroke, RIC) will refer patients and assist with safety monitoring. Dr. Y. Dhaher (Bioengineer, RIC) will provide training in biomechanics and kinematic analysis. RIC has all the laboratory, personal office, and administrative facilities necessary for the study. The Research Plan will assess whether direct current electrical stimulation of the motor cortex is a candidate adjuvant for stroke therapy. Experiments will determine the extent and specificity of cortical modulation in healthy subjects and stroke survivors. A split belt treadmill will be used to induce a robust change in gait symmetry. The main experiment will determine if direct current stimulation applied prior to split belt treadmill walking will enhance gait symmetry in groups of stroke patients with subacute and chronic, cortical and subcortical lesions. The impact on the social well-being of the more than 5.5 million Americans who are stroke survivors is largely dependent on their ability to walk again. The proposed research has the potential to develop a safe, low-cost, easily administered auxiliary treatment for walking retraining that could promote a major increase in walking ability and independence following stroke.